TEHRAN, Iran - Responding to allegations by the U.S. that the Islamic Republic had violated a UN resolution by testing a medium-range ballistic missile, Iran fired back on Monday, threatening to boost its missile program further.

Slamming the country's recent ballistic missile test, the U.S. Secretary of State Mike Pompeo claimed that the test was conducted in violation of a United Nations resolution.

Alleging that Iran's medium-range ballistic missile had the capability of carrying multiple warheads, the top American diplomat called on the country to "cease these activities."

Pompeo claimed that the missile tested by Tehran "had a range that allows it to strike parts of Europe and anywhere in the Middle East."

He warned, "As we have been warning for some time, Iran's missile testing and missile proliferation is growing. We are accumulating risk of escalation in the region if we fail to restore deterrence. We condemn these activities, and call upon Iran to cease immediately all activities related to ballistic missiles designed to be capable of delivering nuclear weapons."

Pompeo further stated, "This test violates UN Security Council resolution 2231 that bans Iran from undertaking 'any activity related to ballistic missiles designed to be capable of delivering nuclear weapons, including launches using such ballistic missile technology...'"

However, a U.S. Defense official, who was familiar with the initial data from the launch pointed out that the missile launch did not appear to determine any capabilities that the U.S. was not aware of.

The U.S. Strategic Command reportedly tracked the Iranian missile test using a satellite network that traces ballistic missile launches.

The officials quoted in reports also said that the missile test did not pose a direct threat and doesn't constitute a violation of the UN measure.

Further, experts immediately noted that Resolution 2231 cited by Pompeo was adopted by the UNSC and endorsed the implementation of the Joint Comprehensive Plan of Action (JCPOA) or the 2015 Iran nuclear deal.

They also noted that the UNSC resolution does not ban Iran from undertaking any activity related to ballistic missiles.

The language quoted in the resolution calls on Iran "not to undertake any activity related to ballistic missiles," but does not forbid Tehran from testing missiles - which means that its test was not in violation of the UN resolution.

However, the U.S. Defense Secretary James Mattis too echoed Pompeo's statement and said, "The threat from Iran is multifaceted."

Mattis said, "Right now the strategic level of threat from Iran is less worldwide than Korea's, but it is certainly significant regionally and it could grow beyond that if it's not dealt with."

Further, the U.S. National Security Adviser John Bolton tweeted, "Iran just test-fired a... ballistic missile capable of reaching Israel and Europe. This provocative behaviour cannot be tolerated."

'Boosting our defences'

Responding to the U.S. Secretary of State, Bahram Qassemi, a spokesperson for Iran's Foreign Ministry rejected Pompeo's claim that the missile test contravenes the UN Security Council resolution.

In a statement posted on the ministry's website, Qassemi said, "Iran's missile program is defensive in nature. There is no Security Council resolution prohibiting the missile program and missile tests by Iran."

Qassemi directly addressed Pompeo in his statement and said, "The interesting and of course farcical point here is that you are referring to a resolution that you have not only violated by unilaterally and illegally withdrawing from the JCPOA, but also you urge others to breach it, and even threaten to punish or slap sanctions on them if they implement the agreement."

Iran has come under intense economic pressure this year, after the U.S. President Donald Trump withdrew the country out of the Iran nuclear deal in May this year.

Subsequently, the U.S. reinstated all the intense sanctions that Tehran had received relief from since 2015, when the deal was signed.

Trita Parsi, President of the National Iranian American Council explained that the UN Security Council Resolution "calls on" rather than "forbids" Iran from testing its missiles.

He said, "We had a functioning deal and you may not have agreed with all the contents of it but it actually contained this conflict. Trump came in, ripped it up and now we are seeing more missile tests, were seeing escalation and we are seeing a drift towards war."

On Monday, a top Iranian military spokesman threatened that the country would continue developing and testing ballistic missiles.

In a statement, Brigadier-General Abolfazl Shekarchi, a spokesman for Iran's armed forces denied that his country had violated the 2015 Iran Nuclear Deal and warned, "Missile tests are carried out for defence and the country's deterrence and we will continue this. We will continue to both develop and test missiles. This is outside the framework of nuclear negotiations and part of our national security, for which we will not ask any countrys permission."